Tablets, capsules, caplets and many other types of devices have been used for oral delivery of active agents. These forms are relatively easy to manufacture and convenient for use in the hospital or other institutional settings or at home. Many different types of active agents have been incorporated into such dosage forms--ranging from analgesics to antibiotics to hormones.
There are patients that, because of age or infirmity, have difficulty swallowing solid oral dosage forms. According to Kikendall et al., Digestive Diseases and Sciences 28:2(1983), there were 221 cases documented between 1970-1982 of tablet and capsule induced esophageal injury. The most commonly implicated drugs were tetracycline (108 cases), emepronium bromide (36 cases), potassium chloride (16 cases) and ferrous salts (12 cases).
In view of the above, various approaches have been proposed whereby swallowing of a large solid system is avoided as is described in the following patents and applications which are all incorporated by reference herein.
U.S. Pat. No. 2,436,505 to DuRall describes a pill douser for administering medicines in liquid form or in pills or tablets. The device has a bowl at the top for containing the medicine and a tube that can be submerged in a liquid held in a drinking glass. The liquid is drawn upward for administering the liquid and any pill or tablet present in the bowl.
U.S. Pat. No. 2,867,536 to Mead et al. describes an improved drinking straw where a soluble flavoring material is contained within an annular space contained within an inner and an outer tube. The inner tube has a bore through which liquid can be drawn. During use, the upper and lower caps are removed, the flavoring material is emptied into the liquid and the flavored liquid is drawn up through the inner tube and into the mouth.
U.S. Pat. No. 3,610,483 to Visconti describes a dispensing device for liquid medication that is formed in the shape of a straw. A predetermined dose of liquid medication is loaded into the straw which is then capped at both ends until the medication is dispensed when a patient removes the caps and sucks air into the device.
U.S. Pat. No. 4,581,013 to Allen is directed to a doser for orally administering a medication. A tube with a removable closure and a radially extending plate supports a solid medication and permits passage of a stream of liquid. The tube is fitted on top of a straw that is placed into a liquid.
U.S. Pat. No. 4,792,333 to Kidder describes a tamper proof package for containing and orally administering a solid substance. A tube has two portions that are separated by a supporting and confining means that supports and confines the solid substance but permits fluid flow. The ends of the tube are hermetically sealed.
U.S. Pat. No. 4,981,468 to Benefiel et al. is directed to a unit dosage form for delivering a therapeutic agent in free-flowing form. A slanted grid supports the dose between two ends of a tube.
PCT Patent Application No. PCT/US96/11812 describes an oral active agent delivery system comprising a hollow chamber that contains discrete units of active agent. A fluid passing retainer prevents release of the discrete units but permits fluid entry into the chamber. The retainer is transportable with the fluid entering the system.
A variety of other oral delivery systems have been described. These include a medicated pacifier (U.S. Pat. No. 5,123,915 to Miller et al.) and a lollipop type device for delivery of a solid medicament (U.S. Pat. No. 5,223,259 to Lackney). None of these devices or the devices described previously provide for the delivery of a solid medicament into the oral cavity as a bolus dose, where the entire dose is delivered as a result of complete mixing of the active agent with a fluid.